ransom_note.cpp

// Given an arbitrary ransom note string and another string containing letters from all the magazines, write a function that will return true if the ransom note can be constructed from the magazines ; otherwise, it will return false.

// Each letter in the magazine string can only be used once in your ransom note.

// Note:
// You may assume that both strings contain only lowercase letters.

// canConstruct("a", "b") -> false
// canConstruct("aa", "ab") -> false
// canConstruct("aa", "aab") -> true

class Solution {
public:
    bool canConstruct(string ransomNote, string magazine) {
        
        int count[26] = {0};
        for(char ch : magazine)
            count[ch - 'a']++;
        
        for(char ch : ransomNote)
            if(count[ch - 'a']-- <= 0)
                return false;
        
        return true;
    }
};